Well, 2 months later and I'm resurrecting this thread with a happy ending (well, I'm happy about how its worked out!)
My heart was broken trying various 2nd hand rev counters, all of which turned out to be sticky or out of calibration. Seems they are a disposable part with no room for maintenance. Best price for a new one was £235! Yes £235.. and thats just for the internals of the rev counter, not including casings etc.
Anyway, I ended up buying an Acewell 3915. Has the lot... digi tacho (bar type and digital reacout), speed, water temp, programmable shift light and all the idiot lights. Also has multiple trip meters which log stuff like max speed (could be risky that!) and max temp etc... Much as I liked the Veypour, it has NO idiot lights and I see a neutral light as a must have item. Oh, and despite some negative reports about these acewells not reading revs well on Hornets, mines 100% which is possibly due to the fact that I got their latest model??...
Fitting this meant I needed a fly screen for protecting the new unit.. so I swopped the single headlight for a pair of dominators and got a wee screen fitted and colour matched.
Just snapped a couple of (crap) pics in the garage last night after the test run... but I'm very happy with this wee digital gem. Oh.... and did I mention that I got the digi dash for £145??
Johnny